1. Field of the Invention
The present invention relates to a wire harness comprising plural wire groups for automotive applications, and to a corresponding wire harness bundling method.
2. Description of the Prior Art
As shown in FIG. 7, a conventional automotive wire harness is manufactured using bundling stands 2 placed at predetermined positions in a wire harness assembly stand 1. The specified number of wire strands W are placed in the wire holders 2a of the bundling stands 2, and are then wrapped with tape 3 to form the wire bundle.
In a wire harness of plural wires bundled as described above, it is preferable to place at the cross sectional center of the bundle, specifically not at the outside of the bundle, any wires that must be positively shielded from noise or any wires for which it is essential to prevent any contact, and therefore shorting, with body panels. Examples of such wires include live power supply lines directly connected to the battery, and/or twisted wires for audio speakers.
With the conventional wire harness manufacturing method thus described, however, the plural wires W inserted to the roughly U-shaped wire holders 2a of the bundling stands 2 are inserted at random from the top opening of the wire holders 2a and gathered. There is no specific means available for positioning and holding selected core wires at the cross sectional center of the bundle. Wrapping the bundle with tape 3 while holding the selected core wires at the center of the bundle is time-consuming, and it is not easy to hold specific wires at the center. In addition, the wires that should be positioned at the center of the wire harness are at times actually positioned at the outside of the wire harness.
While it is possible for the worker to wrap the bundle with tape 3 while holding the selected core wires at the center, this is not possible if it is not known which of the many wires are the specific wires to be placed at the bundle center.
In addition, even if the specific wires are identified and centered in the bundle when the wires are wrapped with tape 3, there are usually plural specific wires to be centered in the bundle, and it is not easy to positively hold all of the specific wires in the center while wrapping the bundle.
As a result, it is difficult to completely resolve the problem of at least some of the specific wires W-S that should be positioned at the center of the wire harness being at times actually positioned at the outside circumference of the wire harness, as shown in FIG. 8.
As shown in FIG. 9, a bundling tool 4 for specifically positioning specific wires has been proposed, such as in Japanese Utility Model Publication (unexamined) No. 1-122574.
This bundling tool 4 comprises three spokes 4b radiating from the outside of a nearly ring-shaped holding member 4a. With this bundling tool 4, the plural specific wires W-S are held in the holding member 4a and secured to the bundling tool 4 with tape, the other wires W are placed around the outside of the holding member 4a holding the specific wires, and the outside of this wire bundle is then wrapped with tape 3 to complete the wire harness.
Because the tape 3 is wrapped around the outside of the plural spokes 4b when this bundling tool 4 is used, the outside diameter of the wire harness must correspond to the outside diameter of the bundling tool 4. As a result, a different bundling tool 4 must be used for each wire harness size (diameter), and cost thus rises.
The opening of the holding member 4a is also large and the holding member 4a opens to the outside. As a result, there will be cases in which all of the specific wires W-S cannot be held at the center of the wire harness because some of the specific wires W-S can easily escape from the holding member 4a, and there is no means of holding the other wires W positioned around the holding member 4a. Wrapping the wire bunch with tape can therefore be a time-consuming and difficult task.